Suction press roll and method for manufacturing same



Dec. 24, 1968 J- E. POST 3,418,205

SUCTION PRESS ROLL AND METHOD FOR MANUFACTURING SAME Filed April 19,1965 2 Sheets-Sheet 1 FIG 2 FIG 3 INVENTOR. JAMES E. POST BY WILFRED g.BARANICK on CHARLES S. MCGUIRE ATTORNEY Dec. 24, 1968 J, 5, POST3,418,205

SUCTION PRESS ROLL AND METHOD FOR MANUFACTURING SAME Filed April 19,1965 2 Sheets-Sheet 2 l2 FIG. 4

FIG. 7

INVENTOR- JAMES E. POST BY WILFRED JHBARANICK United States Patent3,418,205 SUCTION PRESS ROLL AND METHOD FOR MANUFACTURING SANIE James E.Post, South Duxbury, Mass. (62-B Byrne Court, Wayne, NJ. 07470) FiledApr. 19, 1965, Ser. No. 449,035 3 Claims. (Cl. 162-372) ABSTRACT OF THEDISCLOSURE A suction press roll including a perforated metal roll towhich is secured a resilient material having smooth surfaced holesextending radially therethrough which are in alignment with theperforations in the metal roll. The holes can be of substantiallyuniform diameter or provided with a flared portion adjacent to the metalroll. The suction press roll is produced by covering a perforated metalroll with a predetermined thickness of a resilient material in anuncured state, curing the resilient material to a predetermined hardnessin the presence of smooth surfaced elongated inserts of suitableconfiguration which extend radially through the resilient materialcovering and into the metal roll perforations and then removing theinserts.

This invention relates to the extraction of liquid from a rapidly movingweb or sheet and more particularly, to suction rolls useful, forexample, in paper making machines for extracting water from a web ofpulp or paper and to a method for making such rolls.

A principal object of the present invention is to provide improvedsuction rolls for the more efiicient and economical removal of a liquidsuch as water from a rapidly moving web or sheet of material such aspaper.

Another object of the invention is to provide improved suction rollscomprising a perforated metal cylinder or roll covered with a layer ofresilient material having holes or perforations extending radiallytherethrough which possess very smooth surfaces or walls.

Still another object of the invention is to provide improved suctionrolls comprising a perforated metal roll surfaced with a resilientmaterial having very smooth surfaced holes or perforations extendingradially therethrough which are in alignment with the perforations inthe metal roll, the holes in said resilient material being ofsubstantially uniform diameter therethrough.

Still another object of the invention is to provide improved suctionrolls comprising a perforated metal roll or shell to which is bonded orotherwise secured to the outer diameter thereof a covering of aresilient material such as rubber having very smooth surfaced holesextending radially therethrough, the portion or end of the holesadjacent to the roll being flared.

A further object of the invention is to provide a suction press rollcomprising a stationary suction box and a perforated rotatable metalroll orflshell surrounding the suction box covered with a resilientmaterial having holes as heretofore noted.

A still further object of the invention is to provide a method forproducing suction rolls of the above constructions.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the method involving the severalsteps and the relation and the order of one or more of such steps withrespect to each of the others, and the apparatus possessing theconstruction, combination of elements and arrangement of parts which areexemplified in the following detailed disclosure and the scope of theapplication of which will be indicated in the claims.

Patented Dec. 24, 1968 For a fuller understanding of the nature andobjects of the invention reference should be had to the followingdetailed description taken in connection with the accompanying drawingswherein:

FIGURE 1 is an exaggerated fragmentary sectional view of a perforatedmetal roll covered with a resilient material such as rubber illustratingone embodiment of the present invention for providing smooth surfaced,radially extending holes through the resilient material COVeI'Hlg;

FIGURES 2 and 3 illustrate inserts or pegs which may be used inproviding holes of the type shown in FIG- URE 1;

FIGURE 4 is an exaggerated fragmentary sectional view of a perforatedmetal roll covered with a resilient material illustrating the formationof one preferred type of telescope-like hole in the resilient material;

FIGURES 5 and 6 are inserts which may be used to provide holes of thepreferred type in the resilient material covering; and

FIGURE 7 is a diagrammatic view, partially in elevation and partially insection, illustrating a press unit or assemblage utilizing a suctionpress roll of the present invention.

In the manufacture of paper, it is generally the practice to convey aweb or sheet of paper after it is formed on a Fourdrinier wire or othersheet-forming device and which contains about 5 percent :or more ofwater through one or more rotary presses and then through dryers for theremoval of water. In the press part of a paper making machine, the webof wet paper is usually carried by the aid of one or more press feltsbetween rotating pressure rolls for the purpose of squeezing or pressingwater from the web by pressure exerted between the rolls.

The presses usually consist of a rotating pair of rolls, one of whichmay be a suction roll, that is, provided with means for removing waterfrom the paper web by the application of a vacuum. One form of suctionroll frequently employed comprises a metal roll or shell provided with aplurality of perforation-s which rotate past one or more suitablypositioned suction boxes. The outer surface of the roll is generallycovered or surfaced with a layer of a resilient material such as rubberwhich is provided with perforations which are in substantial alignmentwith the metal roll perforations so that the wet paper web conveyedbetween the press rolls is subject to a vacuum for removing watertherefrom. Presses utilizing a suction roll, thus remove water from awet web by means of pressure, suction and centrifugal force.

In the present method for manufacturing perforated rubber coveredsuction rolls, the metal roll or cylinder is first drilled to provide aprofusion of small perforations in a predetermined pattern. Theseperforations may, for example, have a diameter on the order of about Aof an inch and widthwise centers of say, from about to about of an inch.After drilling, the outer surface or circumference of the perforatedmetal roll is covered with a predetermined thickness of uncured orunvulcanized rubber which is then cured to a predetermined hardness. Thecuring or vulcanization of the rubber also aids in the bonding of therubber covering to the metal roll. The roll may be covered with rubberhaving a thickness of from about /8 of an inch to about 1 /2 inches.Generally, the thickness of the rubber covering is on the order of oneinch. Holes are then drilled into the hardened rubber covering toconform with the perforations in the metal roll thus resulting inthousands of small holes extending through both the rubber covering andthe metal roll. The holes resulting in the rubber covering usually areof a smaller diameter than the diameter of the perforations in the metalroll. Typically, the diameter of the holes in the rubber covering may bebetween about and A; of an inch. Upon completion of the drilling of therubber covering, it is then ground, crowned and sanded to the desiredspecifications.

The above practiced method and perforated coated suction rolls producedaccording thereto possess several difficulties. For example, drillingthrough the rubber covering with steel drills and the withdrawal thereofhas a tendency to disturb or weaken the bond between the rubber coveringand the metal roll which may result in the separation of the coveringfrom the roll. Obviously, separation of the covering from the roll canhave several undesirable exects such as slippage of the covering whichmay cause misalignment of the perforations and thus appreciably reducethe removal of water by suction, or tearing of the covering so as tonecessitate shutdown of the machine. Even minute separations of thecovering from the roll in areas adjacent the holes are very undesirablesince they provide areas where corrosion of the metal roll or shell maytake place. Additionally, drilling the rubber covering results in holeshaving rough or burred surfaces. Such rough surfaced holes areundesirable since they are readily plugged with paper fibers trapped orretained therein by the irregular surfaces.

Plugging of the holes can have several undesirable consein thenon-uniform removal of water from the web. More- 3 over, plugged holesnecessitate costly cleaning and tend to lessen the over-all life of thecovering.

In the present invention, there is provided an improved suction pressroll which eliminates problems or dificulties such as mentioned above.This improved suction press roll, comprising a perforated metal roll towhich is secured a resilient material such as rubber having smooth,slick surfaced holes extending radially therethrough which are inalignment with the perforations in the metal roll, is produced bycovering the perforated metal roll with a predetermined thickness of aresilient material in an uncured state, curing the resilient material toa predetermined hardness in the presence of smooth surfaced insertsradially extending therethrough and into the metal roll perforations,and then removing the inserts thereby providing very desirable smoothsurfaced radial holes in the resilient material. In one embodiment ofthe invention, the holes in the resilient material are formed by pushingor injecting smooth surfaced elongated inserts of suitable configurationor shape into the uncured resilient material so that they extendradially therethrough and into the perforations in the metal roll. Aftercuring the resilient material to a desired hardness, the inserts areremoved by suitable means to expose the holes.

The smooth surfaced holes in the resilient material can be ofsubstantially uniform diameter throughout the length thereof orpreferably, however, of irregular or nonuniform diameter by being flaredat least at the inner end portion thereof. While the holes can beentirely flared preferably only a portion thereof adjacent the metalroll is so provided. The flared portion of the holes may comprise fromabout one-third to about one-half the total length of the holes. In onepreferred embodiment, the telescope-like holes include an outer portionof substantially uniform diameter and an inner flared portion adjacentthe metal roll; the diameter of the outer portion being less than thediameter of the perforations in the metal roll and the diameter of theinner portion gradually increasing inwardly from that of the outerportion to substantially that of the metal roll perforations.

Since the holes are formed through the use of smooth surfaced insertswhich can be readily removed or separated from the resilient materialthe tendency to weaken or destroy the bond between the metal roll andthe resilient material is minimized. Moreover, since the holes areshaped or formed in a molded-like manner to a smooth surfaced insert,the surfaces thereof are also smooth and slick with little tendency forpaper fibers to stick thereto. Thus, these smooth surfaced holes willnot be plugged as readily as drilled holes. Smooth surfaced holesprovided with a flared portion as heretofore noted are particularlyadvantageous since they also permit a greater amount of water to bedrawn from the holes by suction and to be thrown off by centrifugalforce. The greater amount of water present in the flared holes alsohelps to minimize the sticking of paper fibers to the sides or surfaces.

Referring now to FIGURE 1 wherein there is shown a fragmentary portionof a metal roll or cylinder 10 which is provided with a plurality orprofusion of radial perforations 12 therethrough. The roll 10 can befabricated of bronze, brass, stainless steel or other metal or alloyknown in the art to be suitable. The choice of the type of metal oralloy utilized for the roll depends on the service requirements such aspressures, speeds, chemicals, etc. Likewise, the wall thickness of theroll will also depend upon the conditions of service.

The metal roll 10 is provided, usually by gang-like drilling techniques,with a myriad or profusion of holes or perforations 12 predeterminedlyspaced to form a definite pattern. The pattern will depend on the typeof paper or paper board machine, grades of paper or other operatingconditions. The perforations 12 which radially extend completely throughthe wall of metal roll 10 usually are on the order of about of an inchin diameter on circumferential and spaced so that the center to centerdistance is on the order of between about to about /3 of an inch. Theparticular diameter of the perforations and spacing will depend upon theconditions of service.

In covering perforated metal shell or roll 10 according to the presentinvention, a predetermined thickness of a resilient material 14 in anuncured or unhardened state is applied in the form of a continuous sheetor sheets to the outer surface of the roll. The covering or surfacingmaterial 14 is rubber or other polymeric material which can be appliedto the roll in an uncured or unhardened condition and then cured or setby suitable treatment to produce a resilient covering of predeterminedhardness. In order to allow for shrinkage and also for finish grindingto specifications, the material 14 is applied so that the thicknessthereof is in excess of the finished requirements. For example, if a oneinch thick covering is desired on the suction roll, the material 14 isapplied or built up so as to provide a thickness of say, from about 1 51 to 1% inches.

After the desired thickness of uncured resilient material 14 is applied,elongated, smooth surfaced inserts or pegs '16 of desired shape orconfiguration are pushed radially into the material so that they extendinto the perforations 12 in the metal roll 10. Generally, severalinserts are first pushed through the material 14 from the inside of roll10 in order to indicate the pattern of holes in the roll. The remaininginserts usually by gang-like techniques, are then pushed through thematerial 14 from the outside of the roll so that they extend into theperforations 12 in the metal roll 10. The inserts 16 are preferablysufficiently long so that they extend beyond the inner surface of themetal roll wall as well as completely through the covering of uncuredmaterial 14 and the metal roll perforations 12. The inserts which arepreferably hard and rigid can be fabricated of metal, hard plasticmaterial, wood or other material which can be provided with a smoothsurface. Preferably the insert or at least the surface thereof is of amaterial which permits the insert to be readily released or separatedfrom the covering after curing. For example, the inserts can comprise asteel provided with a silicone coating.

FIGURES l, 2 and 3 illustrate inserts which can be utilized when it isdesired to provide the roll covering with circular holes having asubstantially uniform diameter along the entire length thereof. Asshown, in FIG- URES 1 and 2, the inserts can comprise an elongated,smooth surfaced body of uniform circular cross section provided with atapered or pointed end. The diameter of the insert will, of course,depend upon the diameter desired for holes 12. Thus, for example, whenthe metal roll perforations are on the order of W of an inch, the insertdiameter can be such so as to provide finished holes in the coveringwith, say, a diameter of about of an inch or A5 of an inch. In utilizinginserts of the above configuration, they would be pushed into thecovered roll so as to be substantially flush with the outer surface ofthe layer of uncured resilient material such as shown in FIGURE 1.

Insert '18 shown in FIGURE 3 is similar to insert 16 except that it isprovided with an enlarged head portion which permits the insert to bereadily removed from the outside of the roll.

After the inserts 16 are injected or inserted into place, the covering14 is cured to a predetermined hardness. The inserts are then removed toprovide the desired smooth surfaced holes in the covering of resilientmaterial. In this embodiment, the inserts 16 produce holes having asubstantially uniform diameter therethrough; these holes being alignedwith the metal roll perforations. Generally, the finished holes are asmaller diameter than the diameter of the metal roll perforations.

The removal of the inserts 16 can be accomplished by suitably pushing orpulling them through to the inside of the roll 10. For instance, theinserts can be of a metal or provided with a metal portion which permitsthem to be drawn to the inside of the roll by magnetic means. Uponcompletion of the removal of the inserts, the covering can be finishedground and sanded to required specifications.

The preferred resilient material comprises rubber. In the surfacing of aperforated metal roll with such, uncured or unvulcanized rubber of asuitable thickness is applied to the roll and then after being providedwith inserts vulcanized to a predetermined hardness utilizing knowntechniques or practices. For example, after inserts of appropriateconfiguration have been pushed or inserted into the green orunvulcanized rubber covering so that they extend therethrough and intothe metal roll perforations, the covering is suitably wrapped withcotton or nylon wrapping to extract the air therefrom and to promotegood bonding and hole formation. It should be noted that the raw orgreen rubber closes in about the inserts after they have been pushedtherethrough and that the wrapping helps to insure that the rubber istightly pressed or closed against the inserts. The wrapped roll is thenplaced in a vulcanizer or autoclave for a suitable period of time wherethe covering is cured or vulcanized at an elevated temperature e.g., 290F. with either steam or hot water. After cooling and removal of thewrappings the inserts are removed to expose the desired holes.

In FIGURE 4 wherein like numbers refer to like elements of FIGURE 1, theformation of a suction press roll provided with a covering having apreferred type of telescope-like hole is shown. In this case, theinserts 20 are of a configuration so as to provide the finished holes inthe covering with a flared portion adjacent the metal roll. As shown inFIGURES 4 and 5, the insert 20 can comprise an elongated smooth surfacedbody including an upper portion 22 of a substantially uniform diameter,a central flared or frusto-conical portion 24 and a lower portion 26 ofa substantially uniform diameter which is greater than the diameter ofthe upper portion 22. The lower portion islpreferably provided with atapered or pointed endQAs shown, the diameter of the central portion 24gradually increases from that of the upper portion to that of the lowerportion. A typical insert 20, for example, can comprise an upper portionof a diameter of about A of an inch and a lower portion of a diametersufficient to just pass through metal roll perforations of a diameter ofabout W of an inch. The lower portion can thus be of a diameter of aboutof an inch. The diameter of the central portion 24 in this case willgradually increase from that of the upper portion, that is ,1 of aninch, to that of the lower portion, that is, of an inch.

In utilizing inserts 20, they are pushed or inserted into the coveredroll so that the central flared portion is positioned in the portion ofthe covering adjacent the metal roll. The removal of the inserts 20 canbe accomplished by suitably pushing or pulling them through to theinside of the roll 10.

'-In FIGURE 6 there is shown another type of insert which can beutilized in forming flared holes in the covering. As illustrated, thisinsert 30 comprises an elon gated smooth surfaced body of a generallyfrusto-conical configuration. Preferably this body is provided with atapered or pointed end to facilitate the insertion thereof into thecovering. Inserts of this configuration provide holes which are flaredthroughout, that is, the diameter of the holes gradually increasesinwardly from the outer surface of the covering to the inner surfacethereof.

Referring now to FIGURE 7, there is shown a press assemblage utilizing asuction roll of the preferred construction for the removal of water froma wet paper web. After a water ladened paper web or sheet 40 is formed,for example, in the Fourdrinier, it is conveyed at a high speed by oneor more porous press !belts 42, generally of felt between the nip 44 ofan upper roll 46 and a lower suction press roll 48 in order to press orsqueeze water from the paper web 40. The upper press roll 46 can be ofwell-known construction but preferably comprises a hollow roll ofsintered metal having a predetermined porosity which is provided withmeans for heating it at least in the area of and adjacent the nip.Preferably, the sintered roll is provided with means for supplying a hotgas under pressure thereinto so as to heat it and to provide a flow ofhot gas therethrough. Upper press rolls of the desired construction aremore fully discussed in my US. Patent No. 3,162,568.

The lower suction press roll 48 is shown as comprising a rotatable metalcylinder or shell 50 having perforations 52 extending radiallytherethrough. Secured to the outer surface of cylinder 50 is a layer ofresilient rubber 54 having smooth surfaced holes 56 radially extendingtherethrough and in alignment with the cylinder perforations 52. Theholes 56 in the rubber covering or layer 54 comprise an outer portion 58of substantially uniform diameter and an inner flared portion 60 thediameter of which gradually increases inwardly from that of the outerportion 58 to substantially that of the perforations 52 in the metalcylinder 50. A suction box 62 is mounted within the cylinder 50 todefine a localized suction in the area of the pressure nip 44. As therapidly moving felt 42 and paper web 40 pass through the nip 44, wateris pressed and sucked therefrom into holes 56. Some of the water inholes 56 is withdrawn through holes 52 by means of suction and some isthrown or spewed out by centrifugal force. The removal of water from thepaper web is thus achieved through a combination of pressure, suctionand centrifugal force.

The provision of smooth surfaced flared holes in the suction roll coversuch as holes 56 above is particularly desirable since they permitgreater water removal. Moreover, such holes are not readily plugged orclogged and thus there is little or no interference with the suctionaction. Furthermore, such holes can be easily and readily cleaned suchas by blowing air therethrough or by being treated or washed with anaqueous solution containing a cleansing agent, e.g., a soap ordetergent.

Since the preferred flared holes have a greater volume, they provide agreater reservoir of water to be drawn therefrom by suction and to bethrown out by centrifugal force. Additionally, the greater amount ofwater present in the holes tends to minimize the sticking of paperfibers to the surfaces or sides thereof thus preventing plugging andpermitting maximum suction and centrifugal force action or efliciency.

Furthermore the smooth surfaced holes of the present invention havelittle tendency for paper fibers to stick thereto and thus plugging ofthe holes is minimized. The smooth hole surfaces also permit the maximumamount of water to be withdrawn by the pull of the vacuum and to bethrown off by centrifugal force.

It should also be noted that the present method for forming the smoothsurfaced holes in the covering does not disturb the bond between thecovering of resilient material and the metal roll and thus problemsresulting from a loose or partially separated covering are avoided. Itshould also be pointed out that the present suction rolls can beincorporated into equipment now in use and thus does not require thedesigning and purchasing of new equipment.

Although the improved suction press rolls have been described inconnection with a paper making machine, it should be pointed out thatsuch suction rolls are also applicable to other machines such as of thetype used, for example, in the manufacture of asbestos orasbestos-cement products.

Since certain changes may be made in the above apparatus and methodwithout departing from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:

1. A suction press roll comprising a perforated metal roll to which issecured a resilient material having smooth surfaced holes which extendradially therethrough and which are in alignment with the perforationsin the metal roll, at least the inner end portion of said holes beingflared.

2. A suction press roll comprising a perforated metal roll to which issecured a rubber covering having smooth surfaced circular holes whichextend radially therethrough and which are in alignment with theperforations in the metal roll, said holes consisting of an outerportion of substantially uniform diameter and an inner flared portionadjacent said metal roll, the diameter of said outer portion being lessthan the diameter of said perforations in said metal roll, and thediameter of said inner fiared portion gradually increasing inwardly fromthat of said outer portion to substantially the diameter of saidperforations in said metal roll.

3. A suction press roll according to claim 2 wherein said inner flaredportion comprises from about one-third to about one-half the totallength of said holes.

References Cited FOREIGN PATENTS 974,767 10/1950 France.

DONALL H. SYLVESTER, Primary Examiner.

ALBERT C. HODGSON, Assistant Examiner.

US. Cl. X.R. 162-363

